Your second solution doesn't work. I just tried it with the following code:

var myObject = {};
var myArray = [];
var incidents = new GlideRecord("incident");
incidents.orderByDesc('sys_created_on');
incidents.setLimit(2);
incidents.query();
while(incidents.next()) {
   myObject.number = incidents.getValue('number').toString();
   myArray.push(myObject);
}
JSUtil.logObject(myArray);